This invention relates to the removal of surface portions of dead or living tissue, sometimes termed microdermal abrasion or micro-dermabrasion. More particularly, the invention relates to an improved apparatus and process for the abrasion of surface portions of human tissue by the controlled flow of abrasive particles.
Conventional microdermal abrasion apparatuses employ a stream of abrasive particles such as sand applied to the surface of the tissue or skin by means of a vacuum pump through an opening in a hand held tool (termed a handpiece) which is sealed against the skin. The handpiece is passed over the area of skin to be abraded so the particle stream can impinge on the skin through an opening in the handpiece. The spent particles and the removed tissue are then collected by vacuum pressure in the handpiece and are delivered to a collection container for later disposal. Suitable filtration is provided to prevent the escape of the abraded tissue and particles into the vacuum pump and the atmosphere.
Conventional handpieces usually provide a first channel for conducting abrasive particles from a supply container to the area to be treated and a second channel for conducting the spent particles and abraded skin away from the area treated to the collection container.
A typical prior art microdermal abrasion device is shown in U.S. Pat. No. 5,037,432. The hand-held head disclosed in this patent is a long tubular structure including an inlet passage for the abrasive particles and an outlet passage for removal of the spent particles and abraded skin. A treatment orifice in the form of an off-center hole at a 45xc2x0 angle to the longitudinal axis of the handpiece is aligned with the abrasive particle inlet passage to permit the abrasive particle to reach the area of skin to be treated.
The above described handpiece has several drawbacks. Because the treatment orifice is off-axis, the handpiece must be carefully positioned to assure proper contact with the area under treatment, and because it must be held at an angle, is difficult to manipulate over a curved surface such as a human face. As a consequence, the patented handpiece is both uncomfortable and tiring to use.
Moreover, the patented handpiece has been found to be subject to frequent clogging. This requires the operator to repeatedly stop the treatment to clear the blockage.
In addition, the handpiece described above includes a disposable tip or bell section which contains the treatment orifice. The tip is press-fitted onto the body of the handpiece and is tightly sealed thereto to prevent accidental escape of abraded skin and loss of vacuum. This makes it hard to remove for replacement. Further, with the treatment orifice positioned off the longitudinal axis, the tip must be carefully aligned with the particle inlet passage. Although an alignment key on the tip and a cooperating keyway on the handpiece body are provided, the need for proper alignment adds to the difficulty of removal and replacement.
As previously noted, prior art devices typically employ vacuum pumps as the source of operating power. However, the prior art (including the patented device described above) do not provide a convenient way for the suction to be changed by the operator when a weaker or more forceful stream of abrasive particles is desired at particular locations. Similarly, continuously variable control of particle flow rate, i.e., particle volume, has not been provided. Instead, only a single or a few predetermined flow rates are permitted. For example, U.S. Pat. No. 5,954,730, issued to Bernabei, provides a two-position switch operated valve allowing two levels of suction pressure.
In addition, in some conventional handpieces, the tubes leading from the particle supply container and to the collection container are formed integrally with or press-fitted onto the handpiece. This means that the handpiece must also be discarded when the tubes, which are subject to wear due to the effects of the abrasive particles flowing therein, are replaced. This construction also makes sterilization of the handpiece impractical, and sterility of only the replaceable tip can be assured.
In other known devices, threaded fittings are provided for connecting the handpiece to the tubes, such as disclosed in U.S. Pat. No. 5,037,432, issued to Molinari. In this device, however, the diameter of the handpiece is small for ease of handling. Therefore, a tool is required to manipulate the threaded connections, which is both inconvenient and time consuming. Also, the small size of the fittings dictates use of fine threads which have proved to be subject to cross-threading.
Yet a further problem with known prior art relates to the particle supply and waste containers. Typically, the containers are permanent parts of the apparatus so the supply container must be refilled when empty and the waste container must be emptied when full. When either of these operations are performed, clouds of fine abrasive dust are released.
In the case the supply container, this is an inconvenience in that the dust settles on surrounding surfaces and must be removed. Moreover, care must be taken to avoid abrasion when the surfaces are cleaned.
In the case of the waste container, however, the problem is more severe as the abraded skin particles are a source of potential biological contamination to which the operator is directly exposed when emptying the waste container. In addition, the dust cloud released when the container is emptied is a source of environmental contamination.
In one known device disclosed in U.S. Pat. 5,971,999 to Naldoni, a refilled supply container is employed which is then used as the waste container when it is empty. However, these containers are open while they are attached to and removed from the Naldoni machine, so the operator and the environment are still exposed to the clouds of abrasive particles.
In another known device shown in French Patent 2,712,172 to Rabier, a filter bag inside a non disposable outer container is used for waste collection. The full bag is open when it is removed from the outer container, thus again exposing the operator and the environment to the contaminated waste. Also, during disposal, the operator and the environment will be exposed to any contaminated dust which escapes through the filter bag into the outer container.
Moreover, with all of the known devices, various non-disposable parts are permanently mounted on the machine. This makes it difficult, if not impossible, to clean these parts thoroughly.
Yet another problem in the prior art is non-uniform flow and clogging of the abrasive particles in the supply line and the passages of the handpiece. These problems are apparently related in a complex manner to the geometry of the flow passages, and are serious drawbacks in conventional equipment.
According to the present invention, a novel apparatus and process is provided which alleviates the problems with prior art devices as stated above, and which provides other operational improvements as well.
A first aspect of the invention is the provision of a novel handpiece having several important features.
As a first feature, the novel handpiece is comprised of an elongated body portion, a particle supply channel and a waste removal channel extending lengthwise through the body portion, and a removable tip which may be attached to one end of the body portion, A treatment orifice is provided at one end of the tip and is aligned with the longitudinal axis of the handpiece. The particle stream exits the particle supply channel at a point which is radially displaced from the longitudinal axis of the handpiece, but the particle supply channel is so oriented that the stream of abrasive particles is directed substantially toward the center of the treatment orifice. In a preferred embodiment, this is achieved by angularly offsetting the particle supply channel relative to the longitudinal axis of the handpiece.
A further feature of the novel handpiece is the employment of a coupler having internally tapered body portions which mate with externally tapered plug portions to connect the handpiece to the particle supply and waste removal lines. These couplers can be attached and detached simply by twisting the plug portion relative to the body portion, and their use eliminates the need for permanently secured tubes, couplers requiring tools for connection and disconnection or employment of fittings large enough to permit finger manipulation.
According to another feature of the handpiece of the present invention, the diameter of the waste removal channel in the handpiece is substantially larger than that of the particle supply.
According to a second aspect of the invention, a novel particle supply container is provided which controllably aerates the abrasive particles before delivery to the handpiece. In one such supply container, a mixing tube, open at the top, is positioned in the container with its top opening above the particle fill level. The bottom of the mixing tube is connected to a tube which feeds the handpiece particle supply channel. Air is introduced to the container through an inlet opening, and is drawn into the mixing tube by the suction in the system. An opening in the side of the mixing tube near the bottom admits particles under gravity feed, and the particles are mixed with the air stream before exiting the supply container into the particle feed tube. Fine control of the air-particle ratio is provided by a valve which permits additional air to enter the particle feed line just outside the container.
According to another container design, the top of the mixing tube extends through an opening in the top of the container. This eliminates the need for a separate air inlet. Pressure equalization above the level of the particles in the supply container is provided by an outlet hole near the top of the mixing tube.
According to a further container design, a separate air inlet tube is provided which enters the container at the bottom and delivers air through a top opening to the space above the stored particles. Air enters the top of the mixing tube and particles are gravity fed through a hole near the bottom as in the previously described designs.
In other designs, separate particle supply tubes are connected to the mixing tube, and in yet further variations, mixing chambers are provided at the bottom of the container in which the aeration process takes place.
Employment of controlled aeration not only alleviates clogging of the particle flow passages, but also improves the uniformity of particle flow, and permits continuous variable flow rate (particle volume) adjustment.
According to a third aspect of the invention, the particle supply container is designed to be pre-filled by a supplier, installed in a substantially sealed condition, and disposed of in a substantially sealed condition when it is empty. The waste receptacle which receives the spent particles and the abraded skin includes an internal filter also designed for disposal in a substantially sealed condition. This eliminates the need for the operator to refill the supply container and empty and clean the waste receptacle, and even of greater importance, prevents exposure of the operator and the environment to the abrasive particles and the removed skin.
As a fourth aspect of the present invention, there is provided an improved design for a microdermal abrasion apparatus in which an aerated stream of abrasive particles is transported from a pre-filled and disposable supply container having the various features and advantages described above, delivered through a supply tube to an inlet channel in a handpiece, and is delivered from the inlet channel to an axially positioned treatment orifice in a disposable tip at the end of the handpiece. The inlet channel in the handpiece is designed so that the stream of abrasive particles is directed substantially toward the center of the treatment orifice.
Air is evacuated from the tip by a vacuum source connected to a waste removal channel which extends through the handpiece. The spent abrasive particles and the abraded skin, are withdrawn by the suction and delivered through a waste removal line to a combined waste filter and disposal container (referred to below as a xe2x80x9cdisposable waste filterxe2x80x9d or xe2x80x9cwaste filterxe2x80x9d).
The apparatus as described in this aspect of the invention avoids exposure to both clean and contaminated abrasive particles, functions substantially without clogging, provides convenient adjustment of the particle volume and application force, and allows comfortable and convenient use by the operator.
As still another aspect of the present invention there is provided an improved method for microdermal abrasion in which an aerated stream of abrasive particles is transported from a pre-filled and disposable supply container having the various features and advantages described above, delivered through a supply tube to an inlet channel in a handpiece, and is delivered from the inlet channel to an axially positioned treatment orifice in a disposable tip at the end of the handpiece. The incoming stream of abrasive particles is directed substantially toward the center of the treatment orifice.
Air is evacuated from the tip by a vacuum source connected to a waste removal channel which extends through the handpiece. The tip is placed against a surface of the skin to be abraded with the opening in the tip sealed against the skin. The spent abrasive particles and the abraded skin are withdrawn by the suction and delivered through a waste removal line to a disposable waste filter.
Other features of the invention, and advantages over the prior art will become apparent from consideration of the following detailed description in conjunction with the drawings.